Near field detector for integrated surface plasmon resonance biosensor applications

Area of Science:

• Nanotechnology
• Biosensing
• Optoelectronics

Background:

• Surface plasmon resonance (SPR) biosensors offer high sensitivity for detecting biomolecular interactions.
• Traditional SPR systems rely on bulky far-field detectors, limiting portability and integration.
• Developing compact and efficient SPR detection methods is crucial for point-of-care diagnostics.

Purpose of the Study:

• To develop and validate an integrated near-field detector for SPR biosensing.
• To replace conventional far-field detectors with a more compact solution.
• To assess the performance and stability of the novel SPR biosensor system.

Main Methods:

• Integration of a thin-film organic heterojunction diode as a near-field detector below a functionalized gold film.
• Conversion of the surface plasmon evanescent field into photocurrent.
• Characterization of sensor performance, stability, and detection limits in an aqueous environment.
• Comparison of near-field detection with traditional far-field reflectivity measurements.

Main Results:

• The near-field detector demonstrated equivalence to traditional far-field SPR measurements.
• The sensor exhibited stability and reversibility in aqueous solution for up to 6 hours.
• A detection limit of 4 microg/cm(2) was achieved for specific neutravidin binding.
• Simulations predicted a potential maximum sensitivity two times lower than conventional SPR biosensors.

Conclusions:

• An integrated near-field detector can effectively replace far-field detectors in SPR biosensing.
• The developed SPR biosensor is stable, reversible, and offers sensitive detection capabilities.
• Further optimization of device design and surface properties can enhance sensitivity for practical applications.